1. Field of the Invention
The present invention relates to an organic electroluminescent (EL) display and a method of manufacturing the same, and more particularly, to an organic EL display having better photoluminescence efficiency and a method of manufacturing the same.
2. Description of the Related Art
Organic electroluminescent (EL) displays are devices that emit light using energy generated by the recombination of electrons and holes which are injected into and transported in an organic light-emitting layer interposed between an anode, which is a hole injecting electrode, and a cathode, which is an electron injecting electrode. Organic EL displays are self-emitting devices, and include no auxiliary lamps, unlike liquid crystal displays. Thus, research to achieve higher brightness and energy efficiency of organic EL displays continues. The energy efficiency of organic EL displays can be classified into internal quantum efficiency and external quantum efficiency.
A satisfactory level of internal quantum efficiency can be achieved by selecting appropriate materials for the anode, a cathode, and the organic light-emitting layer. However, the level of external quantum efficiency is still unsatisfactory. That is, glass or the like used as an insulating substrate has a refractive index significantly different from that of ambient air so that light that is not emitted outside of the display device trapped inside the display device because of total internal reflection. In this regard, in order to decrease total internal reflectivity, attempts have been made to attach a microlens array to an outer surface of an insulating substrate. Unfortunately, attaching the microlens array not only makes the manufacturing process complicated but is not suitable to applications for a large-sized substrate, which makes the microlens technology impractical.